Kolchak: The Night Stalker (1972). A series of murders plague the Las Vegas strip. An investigative reporter takes up the case himself to attempt helping the local police identify the killer. The case gets odd when anomalies take place during the investigations, such as all victims having their blood consumed to the abnormal features of the killer from witnesses. Kolchak starts to suspect this killer is not exactly human, but the local police show a strong normality bias and rule that out... that is, until Kolchak can find solid proof.